The advent of engineered surfaces in the last decade has produced new techniques for enhancing a wide variety of surfaces and interfaces of materials. For example, the use of engineered surface textures in the micro- and nano-scale has provided non-wetting surfaces capable of achieving less viscous drag, reduced adhesion to ice and other materials, self-cleaning, anti-fogging capability, and water repellency. These improvements result generally from reduced interface contact (i.e., less wetting or non-wetting) between the solid surfaces and contacting liquids.
One of the drawbacks of existing non-wetting surfaces (e.g., superhydrophobic, superoleophobic, and supermetallophobic surfaces) is that they are susceptible to impalement, which destroys the non-wetting capabilities of the surface. Impalement occurs when an impinging liquid (e.g., a liquid droplet or liquid stream) displaces the air entrained within the surface textures. Previous efforts to prevent impalement have focused on reducing surface texture dimensions from the micro- to nano-scale. In addition, existing non-wetting surfaces are susceptible to ice formation and adhesion. For example, when frost forms on existing super hydrophobic surfaces, the surfaces become hydrophilic. Under freezing conditions, water droplets can stick to the surface, and ice may accumulate. Removal of the ice can be difficult because the ice may interlock with the textures of the surface. Similarly, when these surfaces are exposed to solutions saturated with salts, for example as in desalination or oil and gas applications, scale builds on surfaces and results in loss of functionality. Similar limitations of existing non-wetting surfaces include problems with hydrate formation, and formation of other organic or inorganic deposits on the surfaces. Thus, there is a need for improved non-wetting surfaces that have enhanced durability and life expectancy.